Southwest Oncology Group is a cooperative group of institutions that are dedicated to determining better means of treating various types of malignancies in both children and adults utilizing a multimodality approach. This proposal involves only the Pediatric Division of this cooperative group. For newly diagnosed patients treatment protocols are designed which incorporate the most effective known modalities including surgery, radiotherapy, and adjuvant chemotherapy when applicable. Combinations of drugs are being investigated for possible synergistic action. The aim of these studies is to increase the survival and potentially to cure the patient. As a pediatric group of investigators, there is also ongoing concern about the potential late effects of the tumor and/or the therapy used to treat the tumor. These late effects are under investigation. New agents are used in patients with more advanced disease to determine their activity and tumor spectrum in man as well as the appropriate dosage and scheduling. The efficacy of new combinations of drugs is also investigated in patients with advanced disease. All studies are carried out with the informed consent of the patient and/or his parents and the protocols are all approved by the institutional Human Research Committee. For those pediatric tumors with a high incidence of cure the minimal effective therapy is under investigation thus to cut down as much as possible the potential late effects of the treatments. New systems of staging various tumors into several different groups from a prognostic standpoint are also being developed.